United Nations (UN) peacekeeping operations have been increasingly deployed in many crisis contexts. The practice has been established by the UN to ensure peace and protect victims of different types of armed conflict. Unfortunately, during the past ten years, several cases of serious human rights violations committed by peacekeepers against people who should be protected by them have emerged. The UN has gone through a widespread analysis of the issues involved, from the managerial, administrative and legal points of view. The 2005 Zeid Report has provided the basis for further action within the UN system. Since then, several policy and legal measures have been discussed by relevant UN bodies and organs, and some new developments have taken place. This article offers an account and an analysis of the different steps taken within the UN to face difficult cases of misbehaviour, including human rights violations, which may lead to forms of criminal conduct. It takes into consideration the suggestions provided by the Zeid Report and subsequent UN documents. It focuses on legal developments and discusses the main problems in understanding the legal complexity of this phenomenon. The article includes updated documents and proposals that have been discussed and adopted until the most recent reports in 2009.